If Alastair Cook has looked a little short of friends in Australia these past few weeks then he does at least have the most dogged of allies in Ravi Bopara, a team-mate since the age of 14 and a player who in the last three years has flourished in one day internationals under Cook's captaincy.

With England decamped to Perth in preparation for Friday's fourth and penultimate ODI match, Bopara took the opportunity not just to soft-pedal the suggestions from Cook that he might be on the verge of giving up the one-day captaincy, but also to offer a passionate and touching show of support for a man who has been his captain off and on since their days as Essex juniors.

In the course of a refreshingly candid 15-minute question and answer session at the England team hotel, Bopara described Cook as, among other things: "a tough character", "the best player England have", "definitely the man", "definitely a good leader", "in a good place" "well spoken", "always smiling" "definitely the man" (again), "100% the man", "England's leader", "the right man for the job", "the right character", "the right player", "our best player" and (again) "the man".

After a fortnight of bet-hedging, issue-ducking and encoded official statements, Bopara's performance was a refreshingly unequivocal show of fraternal support from a man who, seven years on from his precocious international debut, has matured into an astute and well travelled England cricketer – precisely the kind of ally Cook needs right now as he negotiates the last twitchings of a horribly traumatic tour.

Perth may be the world's most remote major city, and the fourth match of this series may be a dead rubber following England's capitulation in Sydney. But these last two ODIs have a compelling Cook-centred inner momentum all of their own, with England's captain on course for the unique cricketing low of his own personalised ten-match Aussie Cookwash.The series is in effect about Cook now, if only as an uncomfortably voyeuristic exploration of the outer limits of one man's cricketing humiliation.

With this in mind, Bopara was hearteningly steadfast. "[Cook] is in good spirits," he said. "He's a tough character and not much fazes him; it never has in the many years I've known him.

"There is no-one out there who can do the job he can do. He is one of the best players in the England side and has been for a number of years. His experience, his calmness, the respect he has from the rest of the guys, he is definitely the man."

Bopara dismissed Cook's own suggestion in Sydney that he might resign the one-day captaincy as the product of a natural post-thrashing low ("he's only human") and stated his belief – as shared by Andy Flower at the end of the Test series – that whatever it is Cook is learning from the current mauling would simply be thrown away were he not given a chance to put things right. "He is the man to pull us out. I don't see anybody else who can. Everybody sees it the same way. He is our leader. That's how we see it."

Whatever the outcome Cook does have a strong case to stay in the ODI team, having scored four hundreds and averaged 41 since his return in the summer of 2011. His captaincy record, though, is a matter of declining momentum. Of Cook's last 23 matches as captain, 13 have been lost and just four matches won overseas since the apparent new dawn of the 3-0 series win in Abu Dhabi against Pakistan in 2012.

Bopara's point on the apparent lack of alternatives is salient. Eoin Morgan captained England well last summer and has an assertiveness and sense of on-field smarts that would provide a timely sense of contrast. But he has only returned to his best batting form in the last six months and remains, alongside Stuart Broad and – in a more mischievous parallel universe, Kevin Pietersen – the only feasible option among the senior players.

If it was heartening to hear Bopara's words of support for a man he remembers on first impressions as "a skinny kind of guy who couldn't hit the ball off the square" it is hard to avoid the feeling that the only real argument for keeping Cook as captain is the lack of an obvious pre-groomed successor in any format – or in other words another failure of management.